I would practice with the comfortable ribbon, whatever that one was for the particular bow I was trying to learn. And then start doing them in different sizes/widths.

One of the gals on here has a wicked sale going so I was able to get a lot of ribbon at a great price for more variety. I've got a craft show coming up so that was my motivation but with shorter lengths there you can make some for your kiddo and sell the others so it's not 5 yards of the same bows =)

Let me see if I can find that thread and I'll edit my post to link it here!